I've been reading as much as I can about various LED matrices involving both standard LEDs and RGB LEDs. I would like to make something similar to the project here but a bit smaller: macetech.com/blog/?q=node/36

What I originally planned on doing was making a 10x20 LED matrix using only red or blue LEDs and then using it to display sports scores and other news on it. However, I decided that I would like to be able to expand on it in the future, so I'd like to use RGB LEDs even if I only make use of the red or blue to begin with. I don't want to build it using only red LEDs and then have to rebuild everything to add color in the future.

So what I'd like to know is what external hardware should I be looking into in order to control ~200 RGB LEDs using an arduino? Also, I've been using a different board for my class, but I plan on ordering an arduino soon. For what I'm looking to do, which would suit me better, the Duemilanove or the Mega?